Microscopic examination of frozen sections of biological specimens has been done for many years but the methods and apparatus for preparing such specimens is in a comparatively early stage of development.
Frozen section specimens are typically prepared either by immersion of the specimen in a cryogen such as liquid nitrogen or helium, or by bringing the specimen into contact with a super cold surface that has been immersed in cryogen. Previously available cryogenic devices have been rather cumbersome assemblages of equipment in the form of fixed or relatively immobile cryogen tanks with bulky specimen immersion contrivances.
The state of the art is revealed in issued patents such as Sitte, U.S. Pat. No. 4,578,963; Sitte et al, U.S. Pat. No. 4,745,764 and Coulter et al, U.S. Pat. No. 4,751,828.
These patents teach various refinements of the cryofixation process but do not teach hand-held capability of such devices in the manner of the present invention.
The Lightfoot device was developed in response to the need to cryofix specimens where they are found, i.e., in vivo or in surgical environments. However, the present invention is not limited to surgery or the like but is able to perform as a general research tool wherever tissue fixations are needed.